Managing the Arthritic TMJ

The natural course of a TMJ disk dislocation disorder consists of initial pain followed by adaptive remodeling as part of a healing process that makes the damaged TMJ once again function like a normal TMJ. The adaptive remodeling involves reshaping of the bones, which makes these TMJs fit the definition of arthritis, especially in older people, but the term may have no clinical implications, because it simply represents a successful adaptation. The joint has healed and is unlikely to ever again cause problems. Subsequently, some jaw muscle symptoms may persist as a subset of postural muscle strain, because the mandible is an integral part of the postural system; and some ear symptoms may persist long after the cause is gone, because the inner ear does not recover well from injury; but TMJ inflammation in people approaching or beyond middle age is rare

 

The successful adaptation is due to fibrosis of the retrodiskal tissues. These tissues, that once provided blood and nerve supply to the TMJ from the area just behind its disk (retrodiskal area), get pulled by the dislocation of the disk into the former disk space, where they get mashed by chewing forces. Initially they often become inflamed, but eventually they lose their nerve and blood supply and convert into a pad of tough scar tissue called a pseudodisk. Pseudodisks look and function so much like normal disk tissue that, for many years, surgeons mistook them for normal disk tissue and routinely diagnosed the disks they removed as elongated; until researchers pointed out that TMJ disks are made of collagen and cannot elongate, and microscopic examination of these reportedly elongated portions of the dislocated disks contained remnants of blood vessels - proof that these areas were not originally disk tissue, but fibrosed connective tissue. The conversion process is pictured below: 

 

ORAL ORTHOPEDIC APPLIANCES - worn during sleep, when the jaw system undergoes its nightly workout, are the only treatment needed by most people; but the type of oral orthopedic appliance that you need depends on the condition of your TMJs, the state of your jaw and neck muscles, and your facial growth pattern. For example, if your jaw muscles have undergone contracture, restoring their normal resting length requires stretching them. If they underwent atrophy because they avoided using chewing forces for a long time to protect an inflamed TMJ, returning their normal strength requires an optimal exercise template. Long-term treatment should optimize the slow continual jawbone growth of adulthood to gradually restore harmonious function, usually by an oral appliance that redirects the forces of nocturnal bruxism to gradually remove the restrictions to healthy facial growth, which were ultimately responsible for the strains that first caused the TMJ damage

 

Healthy facial growth requires a stable natural bite that provides a comfortable, consistent, and stable platform for the jaw muscles to work on and rest against. If the bite keeps shifting, the bony contours of the TMJs keep remodeling to try and fit a moving target. In many people with TMJ disorders, the bite has been destabilized by a change in the height of a condyle (remodeling), and restabilizing it requires moving teeth, grinding down high spots, and/or building up low spots. In a few cases, restabilizing a bite can require significant dental work such as crowns or orthodontics. These options are explained further in THE ROLE OF THE BITE under the tab TMJ DISORDERS.

 

FACIAL GROWTH - After the muscles are rehabilitated and the bite is stable and correctly positioned, treatment can focus on optimizing facial growth to prevent the symptoms from returning, usually by wearing an oral appliance on a long-term basis during sleep that redirects the forces of nocturnal bruxism to remove restrictions to horizontal facial growth that enlarges the pharyngeal airway, which helps prevent obstructive sleep apnea later in life. In most people, the horizontal facial growth involves expanding the upper jawbone and advancing the lower jawbone, but the type of appliance you need depends on your musculo-skeletal build and your facial growth pattern

 

SURGERY of the TMJ cannot yet be used to recapture a dislocated disk. Open surgery can be risky, because a build-up of scar tissue can prevent natural adaptation, so it is generally considered only a last resort. It is generally only necessary if the TMJ has persistent inflammation that cannot be resolved  by oral orthopedic appliances. Closed surgeries, such as arthroscopy and arthrocentesis, in which tubes and inserted into the joint to flush out the inflammatory tissues and sometimes also to perform some manipulation of the joint tissues, are safer. 

   

CONCLUSION

Having an arthritic TMJ does not condemn you to a lifetime of pain. Many people have TMJs that are technically arthritic, but they have fully adapted and are no longer causing inflammation or triggering muscle guarding. Their TMJs do not need direct treatment, but their muscles may. When the TMJs or the jaw and neck muscles need treatment, oral orthopedics can provide relief of the symptoms within days and stimulate the facial growth needed to prevent them from ever returning.